Termux emulates Zsh for me and gives access to apt-get. so I installed nodejs through apt and made the project with react native and expo. compiling the binary for uploading to Google Play Store was a tricky step and I hope to improve the workflow in the future but for now had to cheat. Expo.io provides a build service for free where they will compile and sign your app for you.

ideally i need to get a copy of OpenJDK installed and build with gradle but this was much easier.

Expo also allows you to build an iOS blob from Android entirely assuming you have a way to get it onto an iphone through testflight.

I'd be interested to read a write-up of this.

Maybe React Native?